Historic scripts as MAYBE?

[Patrik Fältström]

On 28 apr 2008, at 06.36, Mark Davis wrote:

> I'll give a concrete case. Let's suppose that IDNA 2008 is issued  
> based on
> Unicode 5.1, and that in the version corresponding to U5.2, PVALID  
> were
> updated to include MODIFIER LETTER RHOTIC HOOK (and it was removed  
> from
> DISALLOWED).

If that change is made in Unicode between 5.1 and 5.2, then from my  
personal point of view, then Unicode Consortium is not keeping the  
level on promise regarding stability that I hope they do.

But if that change has to be made by Unicode Consortium between 5.1  
and 5.2, then the tables document should be updated in sync with the  
deployment of Unicode 5.2, and I think the codepoint should be added  
to the backward compatibility list as DISALLOWED overriding the change  
made in Unicode Consortium.

But, of course, when the tables RFC is overridden by a new one, then  
of course a decision can be made by the IETF to stay in sync with  
Unicode Consortium and allow a backward incompatible change to the  
algorithm.

A big, hard decision. Very very very difficult decision to make given  
the implications in the DNS.

I do know though UTC is very very aware of the implications of making  
incompatible changes, including legal implications regarding  
registrations in the DNS. Because we have had this discussion before.

    Patrik